1. Field of the Invention
The present invention relates generally to computer-assisted design of vehicles and, more specifically, to a system and method of direct manipulation of a mesh model in the computer-assisted design of a vehicle.
2. Description of the Related Art
Vehicle design, and in particular the design of an automotive vehicle, has advanced to a state in which computer-assisted design techniques are frequently incorporated in the development of a new vehicle, or redesign of an existing vehicle. At the same time, enhanced visualization software tools have been developed that allow for interactive display and manipulation of large geometric models, including models developed using computer-aided design (CAD), such as a vehicle model. In the field of vehicle design, the combined use of computer-aided design and visualization techniques are especially beneficial in designing, packaging and assembling the various systems incorporated within the vehicle, to maximize the design and functional capabilities of these vehicles. Advantageously, potential vehicle system designs can be considered in a timely and cost-effective manner by analyzing a digital representation of a proposed design, versus preparing an actual vehicle model.
One aspect of the design process is to construct a geometric model of the proposed design using a technique known as computer-aided design (CAD). Another aspect of the design process is the use of mathematical tools, collectively referred to as computer-aided engineering (CAE), to constrain and guide the designer in evaluating the design. The use of a CAE simulation allows for verification of a design intent and a prediction of a mechanical behavior of the design, including its systems, subsystems and components. CAE simulations are advantageous in particular types of vehicle analysis, such as vehicle safety analysis and structural analysis. Examples of CAE techniques include finite element analysis (FEA) and computational fluid dynamics (CFD). Recent enhancements to the computing power of modem computers has resulted in a reduction in the amount of time required to perform an analysis, such as a CAE simulation. Therefore, CAE tools can be utilized earlier in the product development process and applied to a wider range of product development activities.
Another example of a product development activity that has benefited from enhanced CAE computational capabilities is Design of Experiments (DOE). DOE is an engineering design practice that enables a designer to conduct a series of tests corresponding to variations in a set of predetermined design parameters. One benefit of a DOE simulation is that a test that in the past would require a physical experiment on a physical prototype, can now be performed using a CAE simulation and a geometric model. As a result, the DOE can be conducted in an early phase of the product development process, and proposed modifications to the design can be expeditiously analyzed. For example, an airflow DOE provides aerodynamic information regarding the exterior shape of the vehicle for use in the design of the exterior shape of a vehicle. CFD is utilized to calculate aerodynamic properties, ranging from drag and lift coefficients to wind-noise characteristics, in response to a set of vehicle exterior shape parameters. Since the CFD simulation uses a geometric model of the vehicle, the airflow DOE can be performed early in the design process, before a physical prototype is built.
As is currently known in the art, a CAE simulation, such as a DOE, begins with a CAD model of a particular design, such as the exterior shape of the vehicle. The CAD model is converted into a mesh model, which is a tessellated approximation of an object's surface, known as a finite element mesh. A simulation, such as a CFD analysis, is performed on the mesh model, to generate a response of the system. Based on the response obtained in the CFD analysis, a system parameter is modified. The CAD model is updated in light of the modified system parameters. However, modifying the CAD model in a CAD system is a very time-consuming task that is performed each time a change is made to the system parameter set. Also, the use of a CAD system in updating a mesh model is a time consuming and costly process, since CAD systems generally require significant overhead, including user background, experience and training. Thus, there is a need in the art for a system and method of direct mesh manipulation of a mesh model using mathematical techniques to eliminate the need to update the CAD model each time a design parameter is modified.